The invention relates generally to the field of condom testing equipment for the detection of holes, imperfections and other defects, and more particularly to such equipment which is utilized to test the nipple of closed end portion of the condom. Even more particularly, the invention relates to such equipment which allows the condom nipples to be tested using electrical conductivity as mandrels containing the condoms move laterally past the testing equipment.
By virtue of their intended use, it is absolutely essential that condoms provide a complete and impermeable barrier. Minute holes undetectable under visual inspection and excessively thin spots in the condom wall likely to fail in use are unacceptable. Because the manufacturing process produces huge numbers of condoms at a high rate and because the material of construction is purposely very thin and elastic, there is always likely to be a relatively small number of defective products in any production run. Because of this, every condom must be tested prior to packaging and distribution for sale to insure that no defective condoms are supplied to consumers.
One technique for testing a condom involves placing the condom on an electrically conductive mandrel, immersing the condom in water containing an electrical lead and then attempting to pass a current through the water to the mandrel. The condom material acts as an insulating barrier between the water and the mandrel to prevent completion of the electrical circuit, but any hole in the condom will allow the circuit to be completed, indicating that the condom is defective. Advantages of this technique are that low electrical voltages are required and the use of water as a conductive medium provides full contact to all portions of the condom. The major drawback to this technique is that the condoms must be dried prior to packaging. Another drawback is that the technique does not provide an indication of excessively thin spots in the condom wall which may tear in use, since the thin material is still sufficient to prevent passage of current from the water to the mandrel.
Another known testing technique is to attempt to pass a gas through the condom. This technique also fails to indicate excessively thin areas in the condom wall.
Another known testing technique is to replace the conductive water with a conductive mesh material, the mesh being constructed so as to be very non-rigid so that it closely drapes against the condom on the conductive mandrel. The mandrel and condom are rotated while contacting the electrified mesh, and again any defects will allow the current to pass through the condom to the mandrel. A problem with this technique is that because the mesh must have a large amount of open area to achieve the desired flexibility, direct contact against every portion of the condom is not achieved, so a relatively high and thus dangerous amount of electrical current must be usedxe2x80x94typically greater than 50 wattsxe2x80x94to try to insure that the current will arc from the mandrel through a defect to the nearest piece of mesh. The variation in distance from the condom to particular points on the mesh as the condom is moved past the mesh also makes proper calibration of the electrical current difficult. Another problem is caused by the nipple portion of the condom. Because of this change in configuration from the generally cylindrical main body portion of the condom, providing enough contact between the mesh and the nipple material is problematic and defects can be missed.
A third and much improved technique is disclosed in U.S. Pat. No. 6,160,406, issued Dec. 12, 2000, to Underwood et al., in which a condom testing apparatus utilizing an arcing electrical current to detect holes and excessively thin wall areas in a condom mounted on a conductive testing mandrel is described, where the condom is passed across a conductive fabric member to test the main body and transition portion of the condom, and is passed through the bristles of a conductive brush member to test the nipple end of the condom. In alternative embodiments, the apparatus may utilize only conductive fabric or only conductive brushes.
It is an object of this invention to provide a highly efficient and accurate condom testing apparatus for the nipple area of a condom to detect any and every defect in the forward end of the condom, including a defect consisting of an excessively thin wall portion which may fail during use, without requiring excessive preparation or post-testing steps in the testing process. It is a further object to provide such an apparatus wherein the testing is performed rapidly such that the processing time for each condom is extremely short. It is a further object to provide such an apparatus wherein the condoms are tested while disposed on test mandrels which pass rapidly through the testing area. These objects, as well as other objects which will be apparent from the description to follow, are accomplished preferably by providing an apparatus having multiple nipple testing housings each having concave nipple-receiving cavities, with the housings mounted onto a rotating mechanism such that the cavities are brought into contact with the nipples of condoms mounted onto mandrels which pass laterally in rapid manner. Preferably, any defects in the condom nipples are detected by electrical arcing which occurs between the electrically conductive mandrels and the electrically conductive nipple-receiving cavities.
In general the invention comprises a condom testing apparatus which has means to transport a condom loaded onto an electrically conductive testing mandrel to bring the condom nipple portion into contact with electrically conductive nipple testing means comprising a nipple-shaped cavity, with the mandrel and nipple testing means connected in a gapped electrical circuit such that the condom acts as an electrical insulator to prevent completion of a circuit between the components of the testing equipment, but where the electrical current will arc between or through any defect in the condom nipple, such as a hole or excessively thin area in the condom wall, to complete the circuit, thus providing an indication that the condom is defective. The mandrel is shaped to correspond to the condom shape, including in particular the forward nipple portion. The nipple-shaped cavity is correspondingly shaped such that the gap between the mandrel nipple and the cavity wall is relatively uniform and minimal, being sized for optimum detection without excessively contacting the condom material such that detrimental friction effects may result. Preferably, the nipple-shaped cavity is formed of a compressible, conductive foam material.
Preferably, two or more nipple testing housings, each comprising a nipple-shaped receiving cavity, are mounted onto rotation means such that each housing moves in a circular arc between an engaged testing position and a non-engaged neutral position, such that the housings align with alternate mandrels as the mandrels are linearly moved past the testing location. The housings are connected by a pair of linking bars, and each bar has a separate pivot point, such that when the linking bars are rotated the housings move over a circular path with the cavity openings always facing in the same direction. The rotation of the housings is synchronized with the lateral movement of the mandrels, such that each nipple-testing cavity is advanced toward and removed from the mandrel without need for slowing the lateral movement of the mandrels.